Method and apparatus for inhibiting bacterial growth in automatic icemakers

ABSTRACT

In an automatic icemaker of the type used in automatic vending machines, the ice cubes, chunks or slush are normally stored in a compartment. In many instances melt-down liquid from the stored ice is allowed or circulated to return and join the water in the freezing chamber. With water at these low temperature levels, the network must be cleaned out periodically to prevent growth of bacteria, slime and other contaminants, both in the storage compartment and in the entire water network. The present invention provides a method and apparatus for automatically sanitizing the water network periodically. The sanitizing cycle includes heating the water in the network to a sanitizing temperature and recirculating the heated water throughout the network. Stored ice is melted and its water may be allowed to join with the circulating water. Once the water in the network has reached the desired sanitizing temperature, it is maintained at that level long enough to ensure the destruction of any bacteria and slime which may have formed. Naturally the sanitizing cycle is set to occur during periods when the icemaker is normally not being used.

United States Patent [191 Pearl et al.

[54] METHOD AND APPARATUS FOR INHIBITING BACTERIAL GROWTH IN AUTOMATIC ICEMAKERS [75] Inventors: Donald C. Pearl, Lake Zurich; Arthur P. Gross, Bensenville, both of I11.

[73] Assignee: Canteen Corporation, Chicago, Ill. [22] Filed: May 17, 1971 [2]] Appl. No.: 143,888

Primary ExaminerWilliam E. Wayner Attorney-C. Cornell Remsen, Jr., Walter J. Baum,

Paul W. Hemminger, Charles L. Johnson, Jr., James B. Raden, Delbert P. Warner and Marvin M. Chaban m1 3,733,840 [4 1 May 22,1973

[57] ABSTRACT In an automatic icemaker of the type used in automatic vending machines, the ice cubes, chunks or slush are normally stored in a compartment. In many instances melt-down liquid from the stored ice is allowed or circulated to return and join the water in the freezing chamber. With water at these low temperature levels, the network must be cleaned out periodi cally to prevent growth of bacteria, slime and other contaminants, both in the storage compartment and in the entire water network. The present invention provides a method and apparatus for automatically sanitizing the water network periodically. The sanitizing cycle includes heating the water in the network to a sanitizing temperature and recirculating the heated water throughout the network. Stored ice is melted and its water may be allowed to join with the circulating water. Once the water in the network has reached the desired sanitizing temperature, it is maintained at that level long enough to ensure the destruction of any bacteria and slime which may have formed. Naturally the sanitizing cycle is set to occur during periods when the icemaker is normally not being used.

14 Claims, 6 Drawing Figures Patented May 22, 1973 3,733,840

5 Shuts-Sheet 1 '1; Y DONALD PEARL F/& 1 ARTHUR I? 690 Patented May 22, 1973 5 Shoots-Sheet 2 Patented May 22, 1973 5 Shuts-Shani 5 A mm W W SQ A A Patented Ma 22, 1973 3,733,840

S Shuta-$hoot 4 Patented May 22, 1973 5 Shuts-Shoat 5 vs? W M11 QQ METHOD AND APPARATUS FOR INHIBITING BACTERIAL GROWTH IN AUTOMATIC ICEMAKERS BACKGROUND OF THE INVENTION Automatic icemakers have become used in a number of areas such as domestic refrigerators, industrial icemaking and in vending machines. It is for the last of these listed uses that the invention has been specifically designed, however, the system shown is capable of use in a number of such applications.

In the field of vending machines, it has been popular for many years to provide cold drink machines with icemakers which manufacture ice for dispensing into a drink along with syrup and water or carbonated water. Icemakers of this type are well-known in the art, for example: U.S. Pat. Nos. 3,196,624 and 3,196,628 both issued to Reynolds July 27, 1965 and U.S. Pat. No. 3,059,450 to R. J. Mueller et al. issued Oct. 23, 1962.

In those patents there are shown icemakers available for use in a number of applications but primarily designed for use in cold drink vending machines. The icemakers shown have a vertical axis cylindrical freezing chamber to which water is fed from a separate water tank. In the chamber, an auger mechanism elevates frozen ice chips to a storage compartment physically located above the freezing chamber. Frequently in such installations, melt-down liquid from the compartment flows back into the chamber, directly or by conduit, and may collect in low areas within the system. During periods of continued use, water circulates and maintains the fresh condition of the water. When, however, the machine is not used for prolonged periods such as nights or weekends, the collected liquids may tend to stagnate, if stagnation is not prevented. It is to solving this problem that the present invention is directed.

The usual method of preventing water stagnation and inhibiting bacterial growth is periodic manual cleaning and flushing out of the system, usually with chemicals. Another approach shown in US. Pat. No. 3,369,376 to Kious issued Feb. 20, 1968 included the concept of drawing liquid by suction from the storage compartment during the normal operating cycle of the machine feed pump. While this concept may have lessened the frequency of maintenance required, the machine still had to be manually cleaned out periodically to destroy bacteria and algae formed and to leave the machine in a clean and sanitary condition.

SUMMARY OF THE INVENTION The present invention contemplates the use of an auxiliary apparatus to control a sanitizing process which operates periodically on a timed basis. The time base is selected to operate the auxiliary system during periods when the machine would normally not be used. Once operated, the auxiliary system continues its cycle for a predetermined time interval calculated to melt all stored ice and to sanitize the water within the icemaking system and the water and ice bearing components within the system. Alternatively the system may use condition sensors such as temperature level sensing to determine cycle duration. Operating components of the machine are inactivated, and a machine out-oforder signal is actuated during the operating interval of the apparatus to deter inadvertent use of the machine during that interval.

During the operating interval, water in the water storage tank is heated and circulated throughout the system to melt any ice in the system and to elevate the temperature of the water to a sanitizing level and to heat the water-bearing components, thereby destroying bacteria which may have grown. In this way, the tendency of quiescent water to stagnate and form slime is eliminated.

It is therefore an object of the invention to provide a new and improved system for automatically controllingand reducing the reproduction of algae and bacteria in an icemaker water feed system.

It is a further object of the invention to provide an improved method of sanitizing the feed water network of the icemaker of a cold drink vending machine.

It is a still further object to provide an improved automatically operative sanitizing apparatus for an automatic icemaker.

It is a still further object of the invention to produce a newand improved cold drink vending machine.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects, features and advantages of the invention will become apparent from the specification when viewed in conjunction with the drawings in which:

FIG. 1 is a schematic diagram of the liquid circulatory system using our invention;

FIG. 2 is a schematic perspective view of the water tank and icemaker subsystem;

FIG. 3 shows a block diagram of the major circuitry used for the vending machine;

FIGS. 3a and 3b comprise a schematic circuit diagram of the relevant portions of a vending machine using a first embodiment of our invention, with FIG. 3b aligned to the right of FIG. 3a; and

FIG. 4 is a schematic diagram containing a revision of FIG. 3a showing a second embodiment of our invention.

DETAILED DESCRIPTION OF THE DRAWINGS In FIG. 1, we show the relevant portions of a liquid circulation system employing our invention as utilized in a cold drink or soft drink vending machine. In that system, we show a valve connection 12 to a supply of potable water. A pipe or conduit 14 leads from the connection to a filter member 16 from which a further conduit 18 leads to a valve 20.

From valve 20, a conduit 28 leads to the top of a water storage tank or reservoir 30. The reservoir 30 serves the main storage for water to be used in the machine. Water enters the tank through a removable, screen enclosure 32 which houses the inlet air gap (not shown). The air gap is required by most municipal plumbing codes, and of course its function is wellknown in the art. In the specific tank shown herein, the water level control function is performed by a plurality of electrodes positioned physically in the tank and operative in the circuit of FIG. 3 and shown schematically therein. From the water tank 30, water flows by gravity through conduit 40 to the positive displacement pump 42. Pump 42 on operation pumps a metered quantity of water through conduit 44 and cooling coils 46 immersed in a water bath (not shown) to cool the water in its passage to either the dispensing conduit 50 or to the carbonator 52 by way of three-way valve 60. The carbonator which mixes carbon dioxide from tank 62 with water may feed its output through carbonated water nozzle 64 for flow into the drink cup 66, when required.

Another output conduit 70 from water tank 30 connected adjacent the bottom 72 of the tank feeds water by gravity to the base of the icemaker chamber 74. The icemaker may be of any suitable type such as one of those previously referred to. In an icemaker of either type referred to, ice is formed in chamber 74 and augered upwardly through tube 75 (FIG. 2) into ice storage compartment 76. Ice is stored in the compartment 76 and is delivered on demand (by means not shown) to the cup 66 for inclusion in the drink being prepared. Within the compartment 76, agitator rods 77 are continuously rotated to churn the ice chips and prevent agglomeration of the chips into a frozen mass.

To provide an outlet for melt-down liquid, a conduit 80 from compartment 76 is connected into the icemaker feed conduit 70 to recirculate melt-down liquid to the icemaker. Conduit 80 may be omitted if a ready return path from compartment 76 to chamber 74 is present inherently in the system.

Within the system as described heretofore, an auxiliary water circulatory path comprising conduit 90 is connected by Tee fittings 92 and 94 into respective conduits 40 and 70, as shown in both FIGS. 1 and 2. A small volume water pump 96 is installed in conduit 90 to pump water from tank 30 to the base of icemaker 74. A check valve 97 directs the flow in the desired direction, as will be described.

Additionally two band heaters 98 and 99 are affixed to the exterior of storage tank 30 and connected to a suitable source of current within the circuit of FIG. 3. We have found that two 100 watt heater bands of any suitable type may serve our purposes.

Turning to FIGS. 3a and 3b, we show our apparatus connected in an electrical circuit to effect its operation. There, we show a conventional source of 110 volt, 60 cycle alternating current, numbered 101. Connected 'directly across the terminals conductors 102 and 103 of source 101 is a timer 110. Timer 110 may have a recurrent operating cycle of 24 hours, or if desired can be a seven-day timer. In either event, the timer, of any commercially available type operates continuously and at a preset time actuates its single contact set 112 for a timed period. Assuming a seven-day recurrent cycle for timer 110, the timer will actuate its contact set 112 each week at the same time and on the same day. Contact set 112 once actuated will remain actuated for a settable timed period which optimally may be between two and two and a half hours. Timer contact set 112 controls the operation of relay 114. Relay 114 has three contact sets. The first set 116 when actuated closes a multiple switch path to the trouble lamp, the second set is normally closed and opens a path to the ice control system, and the third set 119 is normally closed and opens a path to the refrigeration control systern.

Also connected across each terminal conductor is a contactor of main switch 120. The main switch is conventionally used to open the circuit to the system when desired. Within the circuit, the refrigeration system of the machine is indicated by a box 122 with suitable controls indicated by switch 124. An ice control system is represented by box 126.

The multiple selection system which allows choice of flavors and the like is indicated by switch box 130.

Each of the switches in box has connected thereto a solenoid 130a or 130b (only two having been shown) for dispensing syrup or the like.

Also shown is the water control system for feeding water automatically to the feeder tank 30 and maintaining the level constant. Four electrodes 132, 134, 136 and 138 are immersed in the tank 30. A first of these electrodes, 132, provides a ground connection and a second of these, 134, is a low level shut-off controller. On completion of a circuit through water in the tank between electrodes 132 and 134, ground is closed to capacitor 140, to relay and transformer 144 to maintain relay 150 operated.

Relay 150 remains operated so long as water maintains the circuit between electrodes 132 and 134 closed. Relay 150 has a set of contacts 152 which shut down the ice control system 126 on low water level in the tank, a second contact set 154 which opens a multiple switch vend cycle operating path, and a third contact set 156 which will open its own operating path. These contacts are shown in their normal position with relay 150 operated, indicating a sufficient level of water in tank 30.

A third electrode 136 serves as the normal water level feed control by controlling the actuation of relay 160, the water level relay. Relay 160 is normally restored to keep its contact sets 162, 164 and 166 in the condition shown. Contact set 162 provides a shunt ground path for maintaining relay 160 unoperated so long as the electrode 136 is immersed in water. When the water level drops below the level of the electrode 136, the-shunt path is opened to operate the relay 160. Contact set 164 provides a shunt path across contacts 156, and contact set 166 on closure completes a path to the solenoid 170 of valve 20.

When the tank is full, relay 150 remains operated and relay 160 remains inoperative. As the level drops, first electrode 138 is uncovered-and no action occurs. As

the water level continues to drop, electrode 136 becomes uncovered and opens the shunt path to relay 160 which operates. Relay 160 opens its contacts 162 to move control of shunt-off of relay 160 to electrode 138. Valve 20 is energized and feeds water until electrode 138 again is immersed to close the shunt path to relay 160 and de-energize the relay. Capacitor 172 is active as a current limiter to provide protection against hazardous electrical shock.

Electrode 134 is a trouble-indicating electrode such that when the ground path to it through the water is opened, and relay 150 releases, the machine ice control system 126 is de-activated and trouble lamp 174 is illuminated to deter people from inserting money into the machine. Of course, lamp 174 is visible from the exterior of the machine to provide this warning signal.

In the vending machine control portion of the system, there is provided a contact set 178, which responds to coinage in the necessary amount to momentarily close a path to vend relay to prepare a vending cycle for operation. Relay 180 has a first contact set 182 forming a hold path for relay 180, and a second set of contacts 184 preparing a path to the selection system.

When the momentary switch 178 restores to the position shown (having closed for a sufficiently long period to allow relay 180 to have closed contacts 184) and a selection has been made, a path is closed through selection system 130 to cycle timer 190. Cycle timer in the system shown is a motor having a set of cam activated contacts to control the position and duration of phases of a vend operation. Contacts controlled by timer 190 include contacts 191, 192 and 193. Contacts 191 close the operate path to motor 190 for one vend cycle period. Contacts 192 control the water pump 42 to dispense a metered amount of liquid from the tank. Contacts 193 control the dispense control box including a plurality of operating functions not directly germane to this invention, such as cup dispensing, ice dispensing, carbonated water feed and other ancillary functions.

Further in FIGS. 3a and 3b, there is shown a waste bucket switch 196. This switch, as is well-known in the art, senses the level of water in a waste bucket positioned to receive waste water from the dispensing areas and from overflow within the system. Switch 196 is normally closed and on operation opens the main line to the operative elements of the system, and may illuminate a trouble light (not shown) to deter use of the machine thereafter.

Also shown is a cup empty switch 197 which closes a circuit to the trouble lamp 174 to operate that lamp, if necessary. From the circuit, it also can be seen that lamp 174 responds to a low water level in feed water tank 30 to signal a trouble condition and deter use of the machine.

It is understood that many functions of such a machine for vending have been eliminated as not germane to the understanding of our invention, or have been simplified to shorten the disclosure hereof.

During the normal operation of the machine, timer 110 retains its contact set 112 in the position shown in FIG. 3. Relay 114 is therefore inactive. When the clock setting of timer 110 is reached, contact set 112 shifts to close an obvious path to timer relay 114. Contact set 112 once closed remains in that position for the duration of the timed period set on timer 110, retaining relay 114 operated for that period also.

Relay 114 on operation closes contact set 116 to the trouble lamp or sold-out light 174 and holds the lamp illuminated in parallel with relay 114 to maintain the light lit for so long as relay 114 remains operated. This light as mentioned previously is visible from outside the machine and bears suitable legend warning against use of the machine When the light is lit. Also the coin lockout in the rejector is activated to reject any inserted coins.

At contacts 112, the multiple hold path to the vend relay 180 is opened at contact 182 and held open. The same is true of the hold path to cycle timer 190 at contacts 191. Thus, no vend cycle can start during the timed period.

In parallel with timer relay 114 are the small capacity pump 96 and the band heaters 98 and 99 on the water tank 30. The pump is operated by closure of contact set 112 and once operated circulates water within the subsystem of FIG. 2 pumping water from the tank 30 toward the icemaker 74. The band heaters 98 and 99 heat the water in the tank and the water being circulated. It should be noted that the tank 30 is maintained at atmospheric pressure due to the air gap entry so that tion of the water level relay 160 is not interfered with.

The heated water rises in the icemaking chamber and enters the ice storage compartment and returns through melt conduit 80. The check valve 97 prevents the pumped fluid from by-passing the ice chamber and directs the pumped water into the ice-freezing chamber. Thus heated fluid will melt ice in the icemaking chamber and in the storage compartment.

It has been found that starting with the feeder tank water temperature at 70 F., and ice storage compartment filled, it takes approximately 55 minutes for the temperature in the feeder tank to reach a temperature reading of approximately 146 F. The water in the icemaker is then approximately 140 F. The heated water in the ice storage compartment is approximately 6 F. less than the water in the water feeder tank. Waterbased bacteria will not reproduce at these temperatures.

All ice in the storage compartment is melted down in approximately 1 hour and 45 minutes, following which the temperature in the water feeder tank may reach approximately 158 F. The water bearing components of the system and the conduits are also heated by conduction from the circulating liquid and are sanitized during the heating process.

We have found that in two hours, the temperature in the water feeder tank reaches approximately 184 F. At this temperature, bacteria will not reproduce and can be completely destroyed. Tests have indicated that a cycle time of 2 hours is adequate to prevent bacterial reproduction and to destroy any bacteria which has formed, thereby sanitizing the icemaking system and water storage system.

At the end of the timed period which is set, as desired, timer restores its contact set 112 to release the preventive hold on the machine functions. If desired, the lamp 74 and the coin lockout can be maintained in any convenient manner for a period after the release of the timer to deter use of the machine. In this way, using any known techniques, use of the machine can be inhibited for a time sufficient to allow fresh ice to be made and allow the storage water to be cooled. As a practical matter, the sanitization cycle will normally be set to occur during a period when the machine would otherwise be unlikely to be used. For example, in an industrial plant, the cycle would normally be set to start at l or 2 A.M., or at that time on a Saturday or Sunday morning if a practice of weekly sanitizing is to be followed.

In FIG. 4, we show an alternate control mechanism under which the sanitizing once initiated by the timer remains operative under temperature control. FIG. 4 differs from FIG. 3 only in the following areas. Timer 410 of FIG. 4 is one which actuates its contact 412 only momentarily. Momentary actuation of contacts 412 energizes the operating winding of relay 414. Relay 414 is the replacement for relay 114 of FIG. 3 and performs the functions of that relay in addition to other functions as will be described.

Relay 414 once operated closes its contacts 416, 418, 419 (and contacts 118 of FIG. 3b) as previously described for relay 114. Contact set 418 is closed on energization of relay 414 to complete a hold path through temperature sensor 422 to the winding of relay 414. Sensor 422 may be any known thermal sensor or combination of elements which maintains a circuit closed at sensed temperatures lower than a predetermined level and opens the circuit when that temperature is reached. The temperature sensing element may be placed in the water tank to sense the water therein, may be on the the tank wall, or in a suitable location in the recirculatory system or in the ice storage compartment. The only difference for any location would be the condition-changing temperature on which the sensor is to act.

Operation of relay 414 switches its hold path to a circuit including manual switch 424, temperature sensor 422 and closed contacts 418 of relay 414 from the original operating path over timer controlled contacts 112.

In operation of this system, the timer 410 operates its contacts 412 when the sanitizing period is set to start. Contacts 412 close to operate relay 414. The timer contacts 412 restore after a momentary pulse sufficiently long to operate the relay 414. Contacts 416, 418, 419 and 118 close as previously described. Contacts 416 close to energize lamp 174. Contacts 418 open the multiple switch operating path, preventing operation of the machine and also acting in a known manner to return any coins inserted during the lockout period. .Contacts 418 also maintain relay 414, pump 96 and heaters 98 and 99 operative, as previously described.

The sanitizing cycle is begun by the timer and continues under the control of sensor 422. When the temperature sensed by sensor 422 reaches that indicated by experience to mean that sanitizing of the machine has been completed, the circuit through sensor 424 is opened, relay 414 restores due to its hold path having been opened and the machine is restored to its normal condition. As mentioned previously, a time delay may be inserted to prevent operation of the machine during a period sufficient to allow ice to be made and water in the tank to be cooled to near normal levels.

Manual contacts 424 are normally closed and may be opened to open the circuit to relay 414 and stop the cycle, if necessary. Contacts 424 may be pushbutton actuated to end the cycle if a malfunction of any type is noted. Once the system has reset, contacts 412 must close to reinstitute the cycle.

By periodically reinstituting the bacterial inhibiting system described, growth and reproduction of bacteria and slime can be prevented automatically, eliminating the necessity for periodic manual cleanings with chemical agents.

We claim:

1. The process of sanitizing an automatic icemaker system comprising the steps of: initiating the process to heat the liquid in the system, circulating the heated liquid through the system to deter and prevent the growth of bacteria in the system, maintaining the heating and circulating in effect until the heated liquid in the system has sanitized the system, terminating the heating thereafter to allow the system to return to normal, maintaining a deterrent to use of the system as long as the process remains in effect, and for automatically restoring said system to its normal functional condition after the termination of the heating.

2. The process of claim 1 further comprising the step of circulating the heated liquid through an ice storage compartment within said system to melt any ice in said compartment and allow said melted ice to join said circulating liquid.

3. The process of claim 1, wherein the duration of said maintaining of the heating is time controlled.

4. The process of claim 1, wherein the duration of said maintaining of the heating is condition controlled.

5. An apparatus for sanitizing an automatic icemaker fed with liquid from a liquid storage tank over a feed path, comprising a recirculatory network from said storage tank to said icemaker, means for automatically initiating the operation of said apparatus, mean operative responsive to said initiation to heat the liquid in said path, means in said recirculatory network operative to transmit liquid to said icemaker for continuous flow to said tank over said feed path, means settable to operate said heating means for a period sufficient to raise the temperature of the liquid to a sanitizing level and for maintaining said operation of said heating and transmitting means for such period, means operable during said operating period to deter normal use of said apparatus, and means operative automatically following the end of said period for rendering said deterring means inoperative.

6. The apparatus of claim 5, wherein there is an ice storage compartment receptive of ice made in said icemaker and means for causing the circulatory flow to reach said compartment and melt ice for passing melted ice into said recirculatory network.

7. The apparatus of claim 6, wherein there are means from said compartment for normally feeding back melted liquid to said feed path.

8. A sanitizing apparatus for a cold drink vending machine equipped with a water circulating system including an automatic icemaker, an ice storage compartment for storing ice received from said icemaker, a water storage tank for feeding water to said icemakers; the invention comprising means operative to heat water within said system, a recirculatory network interposed between said tank and said icemaker, means in said network operative to pass the heated water through to said icemaker and to said compartment, and means for maintaining said heating means and circulating means operative during a period sufficient to raise the tempen ature of water in said apparatus to a sanitizing level and means for inhibiting use of said machine during said period.

9. An apparatus as claimed in claim 8, wherein said compartment is positioned to receive ice normally from said icemaker and to return melt-down liquid from said compartment, and said circulating means are further operative to circulate said heated water to said compartment to melt the ice therein, and wherein said maintaining means comprising a timer means settable for a timed period of operation of said apparatus sufficient to elevate the temperature of water in the network to a sanitizing level, and means operative at the conclusion of said period for removing the inhibition against use of said machine.

10. An apparatus as claimed in claim 9, wherein said maintaining means includes means for automatically initiating the operation of said heating means and said circulating means at cyclically recurring intervals.

11. In a cold drink vending machine equipped with an automatic icemaker in which there is a circulating system for feeding ice forming liquid to said icemaker, an ice storage compartment and means for feeding melt liquid from said compartment into said circulation system; the invention comprising bacterial growth prevention apparatus operative automatically, heating means responsive to operation of said apparatus for heating the liquid in said system, means in said system for recirculating liquid continuously through said system and into said icemaker and storage compartment, means for maintaining the response of said heating means for a period sufficient to elevate the temperature of the liquid in said system to bacterial growth prevention levels, and for maintaining circulation of the heated liquid to said compartment and said icemaker, means for preventing the normal operation of said machine during said period, and means in said apparatus responsive to the termination of said period for restoring the machine to its normal condition.

12. A machine as claimed in claim 11, wherein said recirculatory means comprises a recirculatory line, a pump therein for recirculating heated liquid and valve means in said line for channeling recirculation through said system.

13. In a cold drink vending machine equipped with an automatic icemaker, including a circulation system for feeding ice forming liquid to said icemaker, an ice storage compartment and means for feeding melt liquid from said compartment into said circulation system;

the invention comprising bacterial growth prevention apparatus, means automatically initiating operation of said apparatus, heating means responsive to operation of said apparatus for heating the liquid in said system, means in said system responsive to operation of said apparatus for recirculating liquid continuously through said system and into said icemaker and said storage compartment, means for maintaining the response of said heating means for a period sufficient to raise the temperature of the liquid in said system to levels destructive of bacterial growthin the storage compartment, and for maintaining circulation of heated liquid to said compartment and said icemaker, and means in said apparatus responsive to the termination of said period for rendering said heating means and recirculating means inoperative.

14. A machine as claimed in claim 13, wherein there is a water tank for feeding fresh water to said system, and said heating means comprises means for heating the water in said tank for recirculation. 

1. The process of sanitizing an automatic icemaker system comprising the steps of: initiating the process to heat the liquid in the system, circulating the heated liquid through the system to deter and prevent the growth of bacteria in the system, maintaining the heating and circulating in effect until the heated liquid in the system has sanitized the system, terminating the heating thereafter to allow the system to return to normal, maintaining a deterrent to use of the system as long as the process remains in effect, and for automatically restoring said system to its normal functional condition after the termination of the heating.
 2. The process of claim 1 further comprising the step of circulating the heated liquid through an ice storage compartment within said system to melt any ice in said compartment and allow said melted ice to join said circulating liquid.
 3. The process of claim 1, wherein the duration of said maintaining of the heating is time controlled.
 4. The process of claim 1, wherein the duration of said maintaining of the heating is condition controlled.
 5. An apparatus for sanitizing an automatic icemaker fed with liquid from a liquid storage tank over a feed path, comprising a recirculatory network from said storage tank to said icemaker, means for automatically initiating the operation of said apparatus, mean operative responsive to said initiation to heat the liquid in said path, means in said recirculatory network operative to transmit liquid to said icemaker for continuous flow to said tank over said feed path, means settable to operate said heating means for a period sufficient to raise the temperature of the liquid to a sanitizing level and for maintaining said operation of said heating and transmitting means for such period, means operable during said operating period to deter normal use of said apparatus, and means operative automatically following the end of said period for rendering said deterring means inoperative.
 6. The apparatus of claim 5, wherein there is an ice storage compartment receptive of ice made in said icemaker and means for causing the circulatory flow to reach said compartment and melt ice for passing melted ice into said recirculatory network.
 7. The apparatus of claim 6, wherein there are means from said compartment for normally feeding back melted liquid to said feed path.
 8. A sanitizing apparatus for a cold drink vending machine equipped with a water circulating system including an automatic icemaker, an ice storage compartment for storing ice received from said icemaker, a water storage tank for feeding water to said icemakers; the invention comprising means operative to heat water within said system, a recirculatory network interposed between said tank and said icemaker, means in said network operative to pass the heated water through to said icemaker and to said compartment, and means for maintaining said heating means and circulating means operative during a period sufficient to raise the temperature of water in said apparatus to a sanitizing level and means for inhibiting use of said machine during said period.
 9. An apparatus as claimed in claim 8, wherein said compartment is positioned to receive ice normally from said icemaker and to return melt-down liquid from said compartment, and said circulating means are furtheR operative to circulate said heated water to said compartment to melt the ice therein, and wherein said maintaining means comprising a timer means settable for a timed period of operation of said apparatus sufficient to elevate the temperature of water in the network to a sanitizing level, and means operative at the conclusion of said period for removing the inhibition against use of said machine.
 10. An apparatus as claimed in claim 9, wherein said maintaining means includes means for automatically initiating the operation of said heating means and said circulating means at cyclically recurring intervals.
 11. In a cold drink vending machine equipped with an automatic icemaker in which there is a circulating system for feeding ice forming liquid to said icemaker, an ice storage compartment and means for feeding melt liquid from said compartment into said circulation system; the invention comprising bacterial growth prevention apparatus operative automatically, heating means responsive to operation of said apparatus for heating the liquid in said system, means in said system for recirculating liquid continuously through said system and into said icemaker and storage compartment, means for maintaining the response of said heating means for a period sufficient to elevate the temperature of the liquid in said system to bacterial growth prevention levels, and for maintaining circulation of the heated liquid to said compartment and said icemaker, means for preventing the normal operation of said machine during said period, and means in said apparatus responsive to the termination of said period for restoring the machine to its normal condition.
 12. A machine as claimed in claim 11, wherein said recirculatory means comprises a recirculatory line, a pump therein for recirculating heated liquid and valve means in said line for channeling recirculation through said system.
 13. In a cold drink vending machine equipped with an automatic icemaker, including a circulation system for feeding ice forming liquid to said icemaker, an ice storage compartment and means for feeding melt liquid from said compartment into said circulation system; the invention comprising bacterial growth prevention apparatus, means automatically initiating operation of said apparatus, heating means responsive to operation of said apparatus for heating the liquid in said system, means in said system responsive to operation of said apparatus for recirculating liquid continuously through said system and into said icemaker and said storage compartment, means for maintaining the response of said heating means for a period sufficient to raise the temperature of the liquid in said system to levels destructive of bacterial growth in the storage compartment, and for maintaining circulation of heated liquid to said compartment and said icemaker, and means in said apparatus responsive to the termination of said period for rendering said heating means and recirculating means inoperative.
 14. A machine as claimed in claim 13, wherein there is a water tank for feeding fresh water to said system, and said heating means comprises means for heating the water in said tank for recirculation. 